1. Field of the Invention
The present invention relates to a high-density optical disk and an apparatus for reading the same, and more particularly, to a high-density optical disk and an apparatus for reading the same by controlling a tracking servo depending on the change between a land and a groove by detection of a mirror area.
2. Description of the Related Art
An optical disk is a non-contact type recording medium, and has developed to achieve high capacity, high speed and high density. In particular, the high-density optical disk medium such as a digital versatile disk-random access memory (DVD-RAM) is used to record and read video information of multimedia or high quality TV. In general, the optical disk has a multitude of tracks which are spirally connected. Referring to FIG. 1, each track has a groove or a land as a user information region. The lands 1LL and 1LR and the grooves 1GL and 1GR form alternate tracks on which information marks 2 are formed. Each track forms a concentric circle which is partially discontinued. A mirror region 19 is formed at the discontinued portions of the concentric circles. A typical guide means 18 formed on the mirror region 19 guides a beam to sequentially access adjacent tracks.
The type of track accessed by the beam is changed according to the track. That is, the type of track is changed from the land 1LL to the groove 2GR or from the groove 1GL to the land 1LR. Therefore, the type of track is identified by information recorded on a header region 14 which is conventionally formed adjacent to the mirror region 19. A tracking servo controller performs a control operation such as a change of the polarity of a tracking error signal according to the identified type of each track.
However, the conventional method which identifies the types of track by using information recorded on the header region 14 results in a loss of the information recording capacity of an optical disk. That is, the special header region 14 must be formed in each track of the optical disk, so user information cannot be recorded on the disk space used by the header region.
Also, since pits 4 representing the types of tracks must be formed on the header region 14, additional processes are required in the manufacture of the optical disk.
To solve the above problems, it is an object of the present invention to provide a high-density optical disk on which a lot of information can be recorded, and an apparatus for reading the same.
Additional objects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Accordingly, to achieve the above and other objects of the present invention, there is provided a high-density optical disk including a land and a groove which are alternately formed to different depths around tracks of a disk and on each of which user information marks are formed; and a mirror region formed at a change between the land and the groove, to guide a beam to sequentially access from a track to an adjacent next track, wherein the land and the groove are formed next to the mirror region, and a change between the land and the groove can be recognized by the detection of the mirror region.
In addition, there is provided an apparatus for reading the high-density optical disk, including an optical detector to detect a beam reflected by an optical disk on which a mirror region is formed between a land and a groove that are alternately formed around the tracks of the optical disk, and converting the detected beam into an electrical signal; a signal processor including a mirror region detector to process the electrical signal to detect the mirror region; and a tracking servo controller to receive the electrical signal from the mirror region detector and to make an appropriate tracking control on the tracks according to a change between the land and the groove.